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Case Study: Integrated System Sidetracks and Drills High-Angle Well in Unstable Formation

Kicking off a whipstock, integrated BHA directionally drills and enlarges 2,719-m section, setting a rotary steerable record in Malaysia

Challenge: Sidetrack out of 13 3/8-in casing and directionally drill a section of at least 2,500 m, enlarging it from 12 1/4 in to 13 1/2 in while building a wellbore inclination angle of 25° to 80° to efficiently run 95/8-in casing.

Solution: Use a TrackMaster CH cased hole whipstock system to mill a casing exit and drill a rathole to run an integrated drilling system that combines a 12 1/4-in M75HSPX PDC bit, PowerDrive Xceed ruggedized rotary steerable system (RSS), arcVISION array resistivity compensated service, and Rhino XS hydraulically expandable reamer.

Result: Milled a window in the 13 3/8-in casing and drilled a 7-m rathole to sidetrack in one trip. Directionally drilled the 2,719-m section while enlarging it from 12 1/4 in to 13 1/2 in with a wellbore inclination angle of 28.1° to 80.6°.

Run casing in an unstable formation

Unable to run 9 5/8-in casing to the bottom of a section due to wellbore instability, an operator working
in Malaysia reasoned that the hole should be plugged and a sidetrack performed from the 13 3/8-in
casing. After sidetracking, the operator wanted to directionally drill a section of at least 2,500 m while
enlarging it from 12 1/4 in to 13 1/2 in, build a wellbore inclination angle from approximately 25° to 80°,
and reduce the vibrations experienced during previous drilling efforts.

Design optimized drilling system to produce wellbore quality

Schlumberger recommended anchoring a TrackMaster CH cased hole whipstock system in the
13 3/8-in casing, milling an exit, and drilling a rathole. To kickoff from the whipstock and directionally
drill the section, an integrated BHA was configured that combined PowerDrive Xceed RSS, Rhino XS
hydraulically expandable reamer, and a 12 1/4-in PDC bit from Smith Bits, a Schlumberger company.

To optimize the BHA for this application, i-DRILL engineered drilling
system design was used to predict formation-generated impediments to
drilling performance, such as vibration and bit cutting action instability.

Deliver stability and durability in record run

The TrackMaster CH cased hole whipstock system milled the 13 3/8-in casing
exit and drilled a 7-m rathole in one trip. The integrated BHA directionally
drilled the 2,719-m section while enlarging it from 12 1/4 in to 13 1/2 in.
Providing stability and durability in the challenging formation, the integrated
drilling system built a high-quality wellbore with an inclination angle of
28.1° to 80.6°, setting a record for the longest RSS run in Malaysia.